I haven't yet hit a deer with the 150 grain bullet, but I see no reason why it wouldn't perform similarly to the 150 grain bullets of other cartridges. It is heavy enough and moving at a good velocity, and it should do the job. The 150 grain bullet gives me pretty acceptible accuracy (less than 1.75" groups at 100 yards with no tweaking), so I think the twist rate is okay from my K98 (I don't know for sure what the twist rate is on a K98). I've even gotten decent accuracy, though not as good (2.25" groups) with the 125 grain bullet, which is super short.
Unless you are wanting less recoil from your 8mm, IMO there is nothing to gain from using the 150 grain bullet. The 185 grainers I use are just as accurate if not moreso, carry more downrange punch, and will penetrate better on tough shots. The trajectory is only minimally different inside 300 yards.